Finding the Fourth Proportional to 1,005.57, 1,385.69 and 725.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.57 : 1,385.69 = 725.31 : x
2. Step 2: Convert to fraction form
   1,005.57/1,385.69 = 725.31/x
3. Step 3: Cross multiply
   1,005.57x = 1,385.69 × 725.31
4. Step 4: Simplify right side
   1,005.57x = 1,005,051.19
5. Step 5: Solve for x
   x = 1,005,051.19/1,005.57
6. Step 6: Final answer
   x = 999.48